move http with proxy call into a helper function

builder/qemu/step_set_iso.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net/http"
 
+	commonhelper "github.com/hashicorp/packer/helper/common"
 	"github.com/hashicorp/packer/helper/multistep"
 	"github.com/hashicorp/packer/packer"
 )
@@ -28,11 +29,7 @@ func (s *stepSetISO) Run(_ context.Context, state multistep.StateBag) multistep.
 
 		req.Header.Set("User-Agent", "Packer")
 
-		httpClient := &http.Client{
-			Transport: &http.Transport{
-				Proxy: http.ProxyFromEnvironment,
-			},
-		}
+		httpClient := commonhelper.HttpClientWithEnvironmentProxy()
 
 		res, err := httpClient.Do(req)
 		if err == nil && (res.StatusCode >= 200 && res.StatusCode < 300) {

common/download.go

@@ -20,6 +20,7 @@ import (
 	"runtime"
 	"strings"
 
+	commonhelper "github.com/hashicorp/packer/helper/common"
 	"github.com/hashicorp/packer/packer"
 )
 
@@ -257,11 +258,7 @@ func (d *HTTPDownloader) Download(dst *os.File, src *url.URL) error {
 		req.Header.Set("User-Agent", d.userAgent)
 	}
 
-	httpClient := &http.Client{
-		Transport: &http.Transport{
-			Proxy: http.ProxyFromEnvironment,
-		},
-	}
+	httpClient := commonhelper.HttpClientWithEnvironmentProxy()
 
 	resp, err := httpClient.Do(req)
 	if err != nil || resp == nil {

common/download_test.go

@@ -5,7 +5,6 @@ import (
 	"encoding/hex"
 	"fmt"
 	"io/ioutil"
-	"net/http"
 	"net/http/httptest"
 	"os"
 	"path/filepath"
@@ -13,6 +12,7 @@ import (
 	"strings"
 	"testing"
 
+	commonhelper "github.com/hashicorp/packer/helper/common"
 	"github.com/hashicorp/packer/packer"
 )
 
@@ -258,11 +258,7 @@ func TestDownloadClient_usesDefaultUserAgent(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	httpClient := &http.Client{
-		Transport: &http.Transport{
-			Proxy: http.ProxyFromEnvironment,
-		},
-	}
+	httpClient := commonhelper.HttpClientWithEnvironmentProxy()
 
 	_, err = httpClient.Do(req)
 	if err != nil {

helper/common/default_client.go

@@ -0,0 +1,14 @@
+package common
+
+import (
+	"net/http"
+)
+
+func HttpClientWithEnvironmentProxy() *http.Client {
+	httpClient := &http.Client{
+		Transport: &http.Transport{
+			Proxy: http.ProxyFromEnvironment,
+		},
+	}
+	return httpClient
+}

post-processor/vagrant-cloud/client.go

@@ -9,6 +9,8 @@ import (
 	"net/http"
 	"os"
 	"strings"
+
+	commonhelper "github.com/hashicorp/packer/helper/common"
 )
 
 type VagrantCloudClient struct {
@@ -37,11 +39,7 @@ func (v VagrantCloudErrors) FormatErrors() string {
 
 func (v VagrantCloudClient) New(baseUrl string, token string) (*VagrantCloudClient, error) {
 	c := &VagrantCloudClient{
-		client: &http.Client{
-			Transport: &http.Transport{
-				Proxy: http.ProxyFromEnvironment,
-			},
-		},
+		client:      commonhelper.HttpClientWithEnvironmentProxy(),
 		BaseURL:     baseUrl,
 		AccessToken: token,
 	}